There has conventionally been known a construction machine with a lower traveling body, an upper slewing body slewably mounted on the lower traveling body, and a work attachment attached to the upper slewing body in a movable manner (e.g., Japanese Utility Model Application Publication No. H5-42349).
The upper slewing body described in Japanese Utility Model Application Publication No. H5-42349 has a main frame that is slewably supported on the lower traveling body and that allows the work attachment to be attached thereto in a movable manner, and side frames fixed to the sides of the main frame.
The upper slewing body also has a cab supported on the side frames and a tank (fuel tank) supported behind the cab on the side frames.
Because the capacity of such a tank provided in a construction machine generally varies depending on the model (size and weight) of the construction machine, a space for installing the tank on the side frame is needed, the space differing in size depending on the model of the construction machine.
Therefore, conventionally, a side frame provided with a tank support portion is prepared with respect to each model of the construction machines, the tank support portion having a size corresponding to the model of the construction machine.
This generates the need to create and manage a side frame for each construction machine model, increasing the costs of the construction machines.